i have an old lethearman micra, and would like to clean it to bring it to its luster. what do you recommend to clean multi-tools? dirt and dine dust in its joints.
Dunk it in some soapy warm water for a few hours, then use toothpicks to pick out the grime - repeat as necessary, then rinse, dry, and lube the joints.
Kroil, WD-40, and/or rubbing alcohol usually work on the gunk that's not water soluable. If it's still not shiny enough to suit, there's always Flitz or Simichrome.
It's different than the ProGold cleaner used on electrical contacts... it's a chain cleaner that's much better for metal-to-metal cleaning and lubricating than WD-40. I use it for my bike chain (Migs - you should try this stuff - it's regarded as one of the better chain lubes out there). It comes in "ProLink" chain lube squeeze bottles, or the PG2000 spray can - same stuff (I checked with ProGold - the ProLink is barely thicker, to the point of not being able to tell), just two different ways of applying it.
It went on the joints of my Micra, which I thought was so mucked up and stiff that it wouldn't be salvageable, and it brought it right back to life!
What I would do? I'd use WD-40 to clean out all the junk. I'd use a toothpick, old toothbrush, or whatever if it needs more. Then I'd let it dry, and after that I'd put a little oil on it, especially the pivots. I don't think there's really a wrong way to do it though. Within reason, of course
NEVER use WD40 !!, its crap, wash it with a chaincleaner and a drop machine oil, thats it.
WD-40 is a deep penetrating oil, and go's everywhere, even on places you don't wanted and after a while it wil rust like hell.
Leatherman tools will rust. Make sure you dry it well and I would use Sentry Solutions' Tuf-Cloth and/or Tuf-Glide (a dry lube & protectant). A wax based lube like KryTech or White Lightning might keep some dirt from working back into the pivots.
Toothpicks and cotton swaps (you can pull off a bit of the cotton if it won't quite fit) will clean out the stubborn grit and grime from the small spaces. It will take a bit of time. Leatherman tools in my experience will tarnish and wear a bit so you probably won't be able to get it back to brand new condition, but it should clean up well.